Although total market penetration of solar into the relevant base of potential customers remains relatively low in the United States (e.g. less than about one percent), residential and commercial solar installs have enjoyed double digit growth since the mid to late 2000s. Despite this recent success, developments to reduce cost, increase efficiency and improve overall home integration are ongoing and must continue to increase solar's market share when compared to fossil fuel-based grid power.
One problem that remains to be solved is an economic and effective solution to improve sealing of roof surface penetrations to prevent water from leaking into the roof structure while providing improved ease of installation. Whether photovoltaic modules are attached to rails, or proprietary rail-free mounting systems, the modules must be securely attached to the roof, which typically involves using a flashing combined with a lag bolt and seal. A pilot hole is typically drilled where the rafter is thought to lie, and if so, is followed by torqueing of a lag bolt into the pilot hole. Generally, the pilot hole is sized for the lag bolt being used, but optionally a larger hole can be drilled as needed. The flashing is then positioned so that the lag through-hole and seal are positioned over the pre-drilled hole. Typically, a puck or other structure is then placed on the flashing and a lag bolt is then passed through the puck, through the through-hole in the flashing and into the pre-drilled hole. The lag bolt is then torqued down to secure the puck to the roof so that the photovoltaic modules can then be mounted to the puck and flashing.
Although flashings cover up a lot of space, potentially covering mis-drilled or off-center pilot holes, flashings are relatively expensive because they require more metal than direct mounted solutions. Also, in order to set the flashing at the proper location, partially under the up-roof course of shingles, it is often necessary to remove existing nails holding down those shingles. Each time a nail is removed, another potential leak point is created. Installing flashing can also require removing or cutting away a portion of an up-roof shingle in order to interleave the flashing among the shingle and provide a flattened area in which to install the mounting puck.
Some installers have utilized direct mount or deck mounted solutions which abandon the flashing in favor of a flat bottomed mounting bracket or foot that is screwed or lagged directly into the roof deck. In cases where the lag is driven through a roof rafter, a single lag bolt may be used. In other cases, where the foot is simply screwed into the plywood that comprises the roof deck regardless of rafter location, three or more screws may be used to achieve the requisite strength. In either case, the holes made in the roof by the lag bolts must be sealed to prevent water from leaking in around the threads of the lag and/or to fill any nearby miss-drilled pilot holes.
To deal with this problem, installers have used caulk or other sealant, typically dispensed from a separate tube or caulk gun to fill these holes as the installation proceeds. This can be messy for the installer, requires a separate large and bulky tool (e.g., caulk gun), and requires another product SKU to be stocked in the truck's inventory. Further, there is no way to ensure that the installer remembers, or even if the installer does remember, that caulk or sealant is actually applied to the lag holes. Moreover, it can be difficult to apply caulk or sealant in the desired area since the mounting puck itself may obscure the area in which pilot holes and the lag bolt penetrates the roof. Therefore, there exists a need for photovoltaic mounting systems that provide reliable and controlled sealing of any penetrations of the roof while improving ease of installation and minimizing mess and installer mishaps. It would be further desirable to provide such improved mounting systems that can be used along with conventional, off-the-shelf components, and without having to rely on metal flashings.